Wednesday, January 2, 2008

Trac-Loc Limited Slip Differential Install

Here are some useful install instructions for this limited slip in the rear of your Jeep.

Starting the project

Jack up the rear and use stands. Remove the rear tires and brake drums. Remove the differential cover and drain all the old gear oil. Next take a good look or picture of you differential. If possible now check the current backlash before removing the carrier. Rotate the driveshaft until you see the large center pin. There is a small bolt that holds the pin in. Remove it and then remove the pin. Now, push in each side of the axles until they stop. You may have to shke them a little. Then go back into the carrier and remove two "C" washers that hold the axle in the carrier. Needle nose pliers work for this. Then There should be 4 large bolts that hold the carrier bearings. Slowly remove those bolts and then be ready. The carrier will fall out and you don't want it on you head. Take the carrier out along with the bearing covers and take it to your bench.

Finishing and putting in the new

Take the new Trac-Lok and press the new bearings on the ends. From expirence, you can't use the old ones, just leave them on your open diff for future use. Once the new carrier has the bearings, the like the open carrier, remove the center pin and then place the unit inside the differential housing. On some rearends, there are shims and others there are threaded bearing caps. On the Chry 8.25 they are threaded and the Dana 35 they use shims. You can purchase shims or most of the time you can use the stock shims. Put the 4 bolts back in for the bearing caps. Tighten to specs. Then it is time to check the (play) backlash. If it is between .005-.010 then you are cooking. If they are not, shim it or rotate the threaded end caps. When you are within specs, push the axles back in. Put the "C" washers back on the inside of the carrier to hold the axles in. Once they are in, you have to pull the axles back out as far as possible. This tightens them up and then makes room for the center pin. Place the center pin back in the carrier and tighen up it's bolt. Put you differential cover back on, make sure you cleaned it out. I used RTV and then sealed it right up. Next I used 80-90 gear oil and a bottle of friction modifer. Put the drums back on and then the wheels. That is it.

1 comment:

ChevWrench
said...

This is "slightly" miss-leading..wheer he says,"the (old)carrier will fall out"-If it does,then it was not "pre-loaded"properly...then he says..."Put the 4 bolts back in for the bearing caps. Tighten to specs. Then it is time to check the (play) backlash. If it is between .005-.010 then you are cooking. If they are not, shim it or rotate the threaded end caps."in reality,The case needs a certain amount of preload in order to load the bearings properly and keep the gears in alignment while under a load.Due to design(the curved design of the teeth on the ring and pinion gears)and the manner in which they work,when a load is applied,the gears will try to climb each another.As this happens,they try to spread apart.If the case/carrier bearings are not properly "preloaded",The gear teeth will climb up each other,thus reducing their contact surface on each other greatly reducing the strength of the teeth and the load they are able to support.This situation WILL result in catostrophic failure of the differential.The proper proccedure for setting up a differential is far more complex than this article would lead one to believe.